Knuckle structure for coupler

ABSTRACT

A coupler having a knuckle provided with a pair of flat surfaces which serve to increase the gathering range over the known prior art couplers. The flat surfaces are of a length and disposed such that the resultant force of the force normal to the surface and the friction force during coupling with a mating coupler is incapable of applying a turning force on the knuckle before coupling with the mating knuckle is achieved.

United States Patent [1 1 Kaufhold [451 Dec. 31, 1974 KNUCKLE STRUCTURE FOR COUPLER Inventor: Horst Thomas Kaufhold, Chicago,

Amsted Industries Incorporated, Chicago, 111.

Filed: Dec. 26, 1973 Appl. No.: 428,256

Assignee:

US. Cl 213/151, 213/109, 213/155 Int. Cl. B6lg 3/04 Field of Search 213/109, 151, 155

References Cited UNITED STATES PATENTS 6/1972 Metzger 213/151 3,779,397 12/1973 DePenti ..2l3/l51 Primary ExaminerM. Henson Wood, Jr. Assistant Examiner-Gene A. Church [5 7 ABSTRACT tant force of the force normal to the surface and the friction force during coupling with a mating coupler is incapable of applying a turning force on the knuckle before coupling with the mating knuckle is achieved.

2 Claims, 11 Drawing Figures PATENTED 3,8571-95 sum 2 or d KNUCKLE OPEN KNUCKLE OPEN PATENTED UECBI I974 SHEET 3 BF 4 PATENTED I974 39857, @955 saw u UP a KNUCKLE STRUCTURE FOR COUPLER BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to couplers and more particularly to an improved contour for a coupler knuckle to increase the gathering range of the coupler.

Coupling of railway cars is generally accomplished with the coupler knuckle on one car closed and the mating coupler knuckle on the other car open. Although under some circumstances both of the couplers may be open. At the same time, the track conditions or the couplers may be located such that the longitudinal axis of the mating couplers are not aligned. In order to achieve coupling it is necessary that the couplers be swung relative to each other during the initial contact so that the coupler axes are brought into axial alignment.

The extent to which the couplers may be axially misaligned and moved into coupling engagement is designated as the lateral gathering range. The gathering range required by the A.A.R. (American Association of Railroads) is a minimum of I inches. This prior minimum gathering range has not eliminated passed couplers during coupling thereby causing coupler or car damage.

Efforts have been made to increase the gathering range by providing flat coupler aligning faces on the knuckle. One example of a knuckle having a flat aligning face is shown in U.S. Pat. No. 3,670,901. HOwever, these prior efforts using a flat coupler aligning face while increasing the distance at which the couplers initially gather have a tendency to close the open coupler prematurely before coupling is achieved.

The gathering ofthe couplers into axial alignment occurs as a result of the forces exerted at the knuckle faces during the initial and subsequent contact. These forces must be sufficient to swing the couplers about the respective butts of the coupler shanks.

At the same time, the forces at the engaging knuckle faces of the couplers must be maintained at level to permit sliding of the knuckle faces as the couplers swing into alignment without causing the knuckle of the open coupler to close prematurely before the tips of the knuckle noses pass into coupling relationship. Should the open coupler be closed prematurely, coupling with a closed knuckle does not occur.

By the present invention it is proposed to provide a coupler having an improved knuckle contour which achieves a greater gathering range than possible heretofore without premature closing of the open knuckle.

This is accomplished generally by the provision of a flat surface on the nose of the knuckle. The flat gathering surface is located on the knuckle to extend between the knuckle side and the guard arm side of the coupler when in the open position thereby to lie in the path of movement ofa knuckle on a mating coupler. To assure the maximum gathering range, the flat gathering surface is located so that the terminal end located on the knuckle side lies on a point at which the resultant force of the force normal to the flat surface and the friction force of a mating coupler is capable of swinging the coupler about the butt of the coupler shank toward a position into axial alignment with the mating coupler.

The gathering surface is also sloped so that the resultant force for the entire length thereof lies either along lines which pass on the knuckle side of the center of the knuckle pivot pin or lie along line-s which pass on the guard arm side and are incapable of applying a force overcoming the resisting friction force at the pivot pin. These friction forces are capable of being determined by test and represented by a friction circle in a vector diagram. The other end of the flat surface adjacent the knuckle tip terminates at a point wherein the resultant force lies along a line on the guard arm side of the center of the pivot pin which is approximately tangent of the friction circle. In this manner the optimum length of the flat gathering surface is obtained without causing premature closing of the knuckle.

A feature of the present invention is the provision of a second flat surface on the knuckle face. The second flat surface is located so that initial contact when the knuckle is closed is made with a mating open knuckle at a greater lateral spacing or gathering distance than was possible heretofore when the surface was curved.

Further features will hereinafter appear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a coupler incorporating the structure of the present invention shown in gathering relationship with a coupler having the prior art knuckle structure.

FIG. 2 is an enlarged fragmentary top plan view of a knuckle incorporating the structure of the present invention and showing the vector resolution of the forces imposed on the gathering surface when the knuckle is in an open position.

FIG. 3 is a fragmentary top plan view of two knuckles incorporating the structure of the present invention showing one of the knuckles in the open position and the other knuckle in the closed position.

FIG. 4 is a view similar to FIG. 3 but showing both couplers in the open position.

FIGS. 5-8 inclusive are schematic illustrations of the couplers of FIG. 3 showing the coupling sequence.

FIGS. 9-11 inclusive are schematic illustrations of the couplers of FIG. 4 showing the coupling sequence.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is shown a coupler 10 incorporating the structure of the present invention. The coupler 10 is shown in coupling mating position with a coupler ll of substantially standard construction. The couplers 10 and. 11 are of substantially identical construction differing only in the structure of a knuckle 12.

The coupler 10 includes generally the knuckle l2 and a coupler head 13 fixed to one end of a shank 14. The shank 14 is provided with a pocket 16 which receives the draft key (not shown). The coupler 10 is swingable about a vertical pivot at its butt 17 in the usual manner.

For convenience the corresponding components of the coupler 11 are identified with the same reference character, but with an a suffix. The coupler 11 includes a coupler head or housing 13a, a knuckle 12a, a shank 14a, a draft key pocket 16a and a butt 17a. The coupler l and coupler 11 are shown with the longitudinal axes 18 and 18a offset with respect to each other.

As is well known the knuckle 12 is attached to the knuckle side 19 of the housing 13 by means of a pivot pin 21 whereby the knuckle 12 is swingable between an open position and a closed position. Similarly, the knuckle 12a is swingable about a pivot pin 21a.

As mentioned above, the couplers and 11 in FIG. 1 are shown offset or laterally displaced to illustrate the gathering range. When railway vehicles are approaching for coupling one or both of the knuckles may be open. Usually, however, coupling occurs with one knuckle open and the mating coupler closed. To achieve coupling, the couplers 10 and 11 must be swung about the respective butt ends 17 and 17a into longitudinal alignment. At the same time, the open knuckle must remain in the open position while sliding along the closed knuckle until the tips 25 and 25a of the noses of the two knuckles pass. After the tips 25 and 25a pass, the open knuckle may be closed into coupling engagement with the mating closed coupler.

When the knuckles 12 and 12a are both in the open position, at least one of the knuckles must remain open so that the tips 25 and 25a similarly pass each other. It should be readily apparent that premature closing of both of the open knuckle will also result in failure to couple.

The coupler knuckle 12 is provided with a flat gathering surface 22. The flat gathering surface 22 is located to lie in the path of movement of a buffing nose on a knuckle of a mating coupler. As shown in FIGS. 1 and 2 the flat gathering surface 22 is sloped at an angle Y with the pulling face as represented by the line 24--24. The angle Y is larger than the friction angle A in order that the knuckles may slide relative to each other. The term friction angle as used herein is the arc tangent of the coefficient of friction at the point of contact.

The magnitude that Y exceeds A is B which is the angle of the resultant knuckle force vector R with the coupler center line 18 and the line of motion X. The couplers l0 and 11 are moved laterally to gather by the transverse component of the resultant force R or by the moment Rd wherein d is moment arm from the pivot point of the coupler butt 17 after overcoming the sum of the carrier friction moment, Wb, and the butt resisting moment, Pa. The uppermost point 0 of the flat surface 22 is selected so that the moment applied by the resultant force R is capable of turning or gathering the couplers about the respective butt pivots.

The knuckles l2 and 12a are slidable relative to each other during gathering movement. The resultant forces R along the length of the surface 22 lie along lines which are disposed on the knuckle side of the axis of the pivot pin and also lie on the guard arm side as the point of sliding contact progresses toward the opposite end 14. The resultant forces lying on the guard arm side creates a turning moment having a moment arm e which tends to turn the open knuckle 12 about the pivot pin 21 to a closed position. The turning of the knuckle 12 about the pivot pin 21 is resisted by the friction resulting from the weight of the knuckle and lock (not shown) and the frictional resistance to rotation about the pin protector, which are represented as a vector as shown in FIG. 2 by the friction circle FC having a radius r which is equal to the product rf wherein r is the pin protector radius at which the force is reached and f is the coefficient of friction of the'frictionally engaging materials on the reacting surfaces.

In order to maintain the knuckle 12 open during sliding movement, the slope and the length of the flat gathering surface is such that the resultant force R does not create an eccentric force e overcoming the resistant force of the pin protector radius r times the coefficient of frictionfcausing the knuckle to turn to a closed position.

As is apparent from FIG. 2 no closing force is created as long as the resultant R force lies on the knuckle side of the center c of the friction circle FC. A resultant force R which lies along a line passing between the center c of the friction circle FC and a tangent thereto on the guard arm side of the knuckle also does not cause the knuckle to close. However, should the resultant friction force R be disposed outside of the tangent to the friction circle FC, it should be readily apparent that the moment arm e thus created would tend to turn the knuckle 12 about the pivot pin 21. By the present invention the end M of the flat gathering surface 22 is located so that the resultant force R at this point passes along a line approximately tangent to the friction circle PC as shown. Thus the resultant forces lying on anyone of the points of contact between 0 and M are incapable of turning the knuckle against the resisting force of the pin protector radius r times the coefficient of friction f. In this manner premature closin of the knuckle is prevented and the maximum gathering range is achieved.

To further increase the gathering range under coupling conditions wherein both couplers ll incorporate a knuckle 12 having the improved flat gathering surface 22, a second flat gathering surface 26 is provided on the knuckle side of knuckle 12. The second flat surface 26 extends from a radius 27 formed at the Q end of the flat surface 22. A second radius 28 is provided at the other end of the second flat surface 26 and is spaced a maximum distance from the radius 27. The length and location of the flat surface 26 is such as to not materially alter the strength characteristics of the knuckle. When the knuckle 12 is in a closed position in flat surface 26 is located such that the point 0 of a mating open knuckle engages the flat surface 26 when the couplers are misaligned as much as 4 Vs inches. Thus there is an increase in the gathering range.

Referring now to FIGS. 3 and 5-8 there is shown the coupling sequence of a pair of knuckles 12 which both incorporate the flat gathering surface 22 and flat surface 26 of the present invention, and wherein the right or bottom knuckle 12 is closed and the left or upper coupler knuckle 12 is open. As shown in FIGS. 3 and 5 at the maximum gathering position, the point Q of the open coupler knuckle engages the flat face 26 of the closed coupler knuckle. The resultant force R at the point Q lies on the knuckle side of the center c of the friction circle FC of the open knuckle so that it remains open. Thereafter, as the couplers swing into axial alignment the open knuckle continues to slide along the flat surface 26 of the closed knuckle until the point M lies adjacent the radius 27. As heretofore explained, the resultant force R at this point lies tangent to the friction circle PC so that the knuckle continues to remain open. During the sliding movement, the resultant force, lies either on the knuckle side of the pivot axis of the pin 21 or within friction circle FC of the open knuckle so that the knuckle remains open between the points M and Q. As the couplers gather into closer axial alignment, the nose tips 25 of the open knuckle engages the closed knuckle at the point 0 of the gathering surface 22 and slides downwardly to the point M and past the nose 25 of the closed coupler. The curvature of the nose tips 25 is conventional and is such that the resultant forces during sliding contact do not close the open knuckle. When the nose tips 25 pass, the open knuckle is rotated to its closed position and coupled with the mating coupler as shown in FIG. 8.

Referring now to FIG. 4 and 9-11 there is shown the coupling sequence of a pair of open knuckles 12 in which both couplers incorporate the improved flat structure of the present invention. The opposing open knuckles contact at the maximum gathering range of about 6 A inches and engage at the points Q of the respective flat surfaces 22. At this point the resultant forces lie along lines on the knuckle side of the center of the pivot pin 21 so that the couplers remain open. As the couplers axially align the resultant force passes through the center of the pivot pin 21 and lies along lines disposed within the friction circle so that the knuckles remain open as explained hereinabove until the surfaces contact at M. In this position the resultant force lies on a line tangent to the friction circle. Thereafter the nose tips 25 pass, as shown in FIG. 10, and the knuckles 12 close to coupled condition as shown in FIG. 11.

I claim:

l. A railway vehicle car coupler comprising a shank and a coupler housing having a guard arm side and a knuckle side, a knuckle, pivot means including pin protector radius means mounting said knuckle on said housing for movement between an open position and a closed position, friction forces resisting turning of said knuckle about said pivot means represented by a friction circle having a radius rf; wherein r is the radius of said pin protector radius means and f is the coefficient of friction at said pin protector radius means, said knuckle having a nose, a flat gathering surface of maximum length on said nose, said flat gathering surface being sloped such that in the open position of said coupler a mating closed coupler is slideable therealong with the resultant force of the force normal to said flat gathering surface and the friction force with said mat ing coupler at one end of the flat gathering surface imparts a moment arm to said coupler capable of swinging said coupler about the butt of said shank, said mating coupler being slideable along said flat face while said knuckle remains in said open position, and said slope of said gathering surface being such that the resultant force at the other end of said gathering surface in the open position of said knuckle lies along a line located approximately tangent to the friction circle.

2. The invention as defined in claim 1 wherein said knuckle includes a second flat surface on the knuckle side of said knuckle face. 

1. A railway vehicle car coupler comprising a shank and a coupler housing having a guard arm side and a knuckle side, a knuckle, pivot means including pin protector radius means mounting said knuckle on said housing for movement between an open position and a closed position, friction forces resisting turning of said knuckle about said pivot means represented by a friction circle having a radius rf; wherein r is the radius of said pin protector radius means and f is the coefficient of friction at said pin protector radius means, said knuckle having a nose, a flat gathering surface of maximum length on said nose, said flat gathering surface being sloped such that in the open position of said coupler a mating closed coupler is slideable therealong with the resultant force of the force normal to said flat gathering surface and the friction force with said mating coupler at one end of the flat gathering surface imparts a moment arm to said coupler capable of swinging said coupler about the butt of said shank, said mating coupler being slideable along said flat face while said knuckle remains in said open position, and said slope of said gathering surface being such that the resultant force at the other end of said gathering surface in the open position of said knuckle lies along a line located approximately tangent to the friction circle.
 2. The invention as defined in claim 1 wherein said knuckle includes a second flat surface on the knuckle side of said knuckle face. 